STUDY OF CHROMOSOME STABILITY OF HUMAN SOMATIC CELLS IN THE DEVELOPMENT OF THE SECONDARY RADIATION-INDUCED BYSTANDER EFFECT.

OBJECTIVE

To establish the level of chromosomal instability in human peripheral blood lymphocytes during thedevelopment of secondary radiation-induced bystander effect.

MATERIALS AND

METHODS

Human peripheral blood lymphocytes; culture of human non-small-cell lung cancer cell lineA549 (irradiated in vitro by 137Cs in a dose of 0.50 Gy/unirradiated). Cytogenetic analysis of uniformly colored chromosomes of human peripheral blood lymphocytes with determination of the frequency of all types of aberrations.

RESULTS

The mean group frequency of chromosome aberrations (4.75 per 100 cells) in human peripheral blood lymphocytes co-cultivated with conditioned culture medium from bystander cells of human non-small cell lung cancercell lines A-549 exceeded the control (1.60 per 100 cells) (p < 0.001) due to an increase in the frequency of singlefragments from 1.20 to 3.95 per 100 cells (p < 0.001). The mean group frequency of chromosome aberrations andchromatid-type aberrations in human peripheral blood lymphocytes during the development of primary (5.80 and4.35 per 100 cells, respectively) and secondary (4.75 and 3.95 per 100 cells, respectively) radiation-induced bystander effect did not significantly differ from each other (p > 0.05).

CONCLUSIONS

Under the conditions of co-cultivation of human peripheral blood lymphocytes with conditioned culture medium from bystander cells of human non-small cell lung cancer A-549, a secondary radiation-induced bystander effect was registered, the cytogenetic manifestation of which was an increase in the level of chromosomalinstability due to the rise in the frequency of chromatid-type aberrations (single fragments). The levels of chromatid-type chromosome aberrations during the development of the primary and secondary radiation-inducedbystander effect did not differ significantly. The development of the secondary radiation-induced bystander effectdid not affect the induction of chromosomal-type aberrations.